@mahks They are used to use what in pos2 is described right after "User Action Attachments", as long as the step is assigned to the same player attached to the user action, then, if the conditions for the user action are met, you will get that user action (all of them), you can click.
User actions work very similarly to political actions.

Simple explanation is that userAction provides the player with a user interface with selections in the form of a separate popup screen and buttons, . The buttons can be used for any logic the mapmaker wants, as long as it is viable with the existing conditions and triggers. This allows the player to make more decisions and provide a real input which interacts (via buttons) with the mapmakers programmed logic.